In the manufacture of automotive vehicles automatic equipment plays an important role in accurate and inexpensive assembly and adjustment of the vehicle components. One of the operations where such automatic equipment has been employed is in the toe adjustment of wheels during wheel alignment. As a matter of design, each vehicle type has an assigned toe angle which is parallel to the longitudinal axis or at a small angle to the axis. To provide an adjustment capability, the tie rod has a threaded adjustment allowing relative rotation of male and female shaft members to cause lengthening or shortening of the tie rod, and a jam nut on the threaded part to lock the assembly against relative rotation. An adjustment machine then must be capable of measuring the toe angle and alternately rotating the jam nut and one of the shaft members for making any needed correction to a high degree of accuracy. The machine then is required to make the measurement and then, without exact information on the location of the tie rod, quickly make the adjustment by finding the tie rod, securely attaching a wrench to the jam nut and the shaft, and rapidly making the proper rotation of each part.
U.S. Pat. No. 4,679,327 to Fouchey et al discloses a toe set alignment system having a track for positioning a vehicle over a pit, adjustment apparatus in the pit, an apparatus for measuring the toe set, a sensor for detecting the vehicle height, and a programmable controller for reading the measurements and controlling the adjustment apparatus. The adjustment apparatus has a mechanism carried on a guideway for positioning relative to the tie rod and an adjustment head having drive rollers for contacting and adjusting the tie rod. A separate nut runner head is used to operate the jam nut. To use the nut runner the adjustment head must first be removed from the tie rod and then, as a separate operation, the nut runner is applied, thereby adding extra time to the adjustment.